Very similar to Air Canada´s system:
1.Promo: The lowest
2.Econo: The best for planned trips
3.Felxi: Adjusted to your budget
4.Super Flexi: Always available
5.Executive: Preferential service and attention.
This is waht i have read in an ad in Semana magazine, i imagine that if you try to book in avianca.com the new system will appear.